1. Field of the Invention
This invention relates to silicone compositions and more particularly, to vulcanizable or curable fluorinated silicone compositions which hare a high vulcanizing speed and whose hardness and physical properties are stabilized within a short time.
2. Description of the Prior Art
As is known in the art, fluorinated silicone elastomer compositions have good resistances to gasoline and oil and are thus useful as rubber parts of aircrafts. A variety of vulcanizable fluorinated silicon elastomer compositions of the addition reaction type used for these purposes have been proposed, for example, in Japanese Patent Publication Nos. 60-27691, 59-31542 and 53-35903 and Japanese Laid-open Patent Application Nos. 56-829, 57-182353 and 59-80464.
In general, fluorinated silicone elastomer compositions of the addition reaction type are formulated with crosslinking agents containing SiH groups. The use of a ##STR2## which has good vulcanizing characteristics, as a main functional group of such a crosslinking agent has been proposed. Moreover, the introduction of a tetrafunctional ##STR3## or a trifunctional ##STR4## has also been proposed so as to provide three ore more SiH groups in one molecule of the crosslinking agent.
However, these known fluorinated silicone elastomer compositions are disadvantageous in that they undesirably take a relatively long vulcanization time of from commencement of the vulcanization till its completion and that a degree of hardness cannot be attained within a short time. For instance, although the fluorinated silicone elastomer compositions are frequently employed as coating and potting materials of various types of hydrid IC or sensors mounted, for example, in automobiles because of its good resistance to gasoline, heating at 150.degree. C. should be continued over several hours until a certain hardness (penetration) is obtained, a long vulcanizing time being thus required.